Researchers produce hydrogen from sunlight, water and rust

As scientists endeavor to increase the efficiency of solar panels, the challenge of storing the resultant energy cheaply and in an environmentally responsible way must also be met. To this end, researchers at Switzerland’s École polytechnique fédérale de Lausann (EPFL) have developed an inexpensive device that transforms light energy into hydrogen, for storage and later use. The new prototype makes use of sunlight, water, and metal oxides, including iron oxide – or rust.

Converting solar energy into hydrogen has been the goal of EPFL scientists for some time, with researcher Michaël Grätzel previously inventing the photoelectrochemical (PEC) tandem solar cell, which also used an iron oxide-based semiconductor, along with a dye-sensitized solar cell, to produce hydrogen directly from water. However, while Grätzel’s approach has merit, it is also prohibitively expensive. Therefore, this new research led by Kevin Sivula was focused on constructing a prototype from only affordable materials and techniques.

“The most expensive material in our device is the glass plate,” explains Sivula. “The efficiency is still low – between 1.4 percent and 3.6 percent, depending on the prototype used. But the technology has great potential. With our less expensive concept based on iron oxide, we hope to be able to attain efficiencies of 10 percent in a few years, for less than US$80 per square meter [10.8 sq ft]. At that price, we’ll be competitive with traditional methods of hydrogen production.”

The current EPFL prototype is completely self-contained and uses electrons stimulated by light to break up water molecules, reforming the resulting pieces into oxygen and hydrogen. This is achieved with a dual system working in tandem: an oxide-based semiconductor performs the oxygen evolution reaction, while a dye-sensitized cell liberates the all-important hydrogen.

As already noted, the semiconductor implemented within the new EPFL research makes use of iron oxide. However, this iron oxide is a little more complex than the rust which is the scourge of car wheel arches, as it has been treated with a nanometer layer of aluminum oxide and cobalt oxide – both of which are easy to apply, but increase the electrochemical properties of the rust markedly.

At this early stage of development, the performance of the rust-based device is still relatively inefficient, making it impractical for widespread use. That said, Sivula predicts the technology will eventually be able to reach an efficiency of 16 percent, while remaining affordable.

The current prototype and the research itself is described in an article published in the journal Nature Photonics.

Adam scours the globe from his home in North Wales in order to bring the best of innovative architecture and sustainable design to the pages of Gizmag. Most of his spare time is spent dabbling in music, tinkering with old Macintosh computers and trying to keep his even older VW bus on the road.

I agree, BigWarpGuy!
This is great! If these people can bump the efficiency of this gadget up to around 10-15% or so (and the fuel-cell makers can put out fuel-cells that don't use platinum), that'll be really great progress.

mooseman

As in other designs there are multiple pathways to gathering energy, not just producing hydrogen. Some of the unused energy can be resolved into an electron flow by an additional junction layer. Next, much of the remaining energy resolves as heat which can be gathered from the backside of the layers on the front, or top face. The final stack could gather as much as 50 percent of the incident energy. Such a panel system is of course more expensive than any single layer system but overall as research lowers the cost of each component as it also improves efficiency you progressively arrive at a panel design that will be affordable and able to beat fossil fuel sources on price.

StWils

Americans who for the most part have neglected the methane available from humanure, manure, and rotting organic garbage, will hardly see purpose to this meagre amount of H2 for the effort. The rest of the world however, who do not ascribe to the American Dream lifestyle, will find that this low cost fuel source could provide just the amount of H2 that they need to survive well.

Bruce Miller

Burning Water has none of these problems and now that the suppressed patents are all over the internet it's coming out of the woodwork.
The Electrostatic Dissociation of distilled water is so clean, portable and brilliant that many intelligent scientists are intimidated by it.
The idea was given patent status after performing proof of concept back in the 1980's. Obviously, when this technology is revealed as workable it will become another huge embarrassment for the U.S., apparently in bed with big oil, and maybe nuclear, coal, and methane.